WAYS IN WHICH SOIL NUTRIENTS CAN BE LOST
(1) Crop Removal
i. Nutrients are removed from the soil by crops for growth, development and production.
ii. When the crops are harvested, the nutrients contained in the plants are never returned to the soil.
iii. The rapid removal of nutrients from the soil by continuous croppingg completely deprives the soil of such nutrients.
(i) Heavy rainfall causes the washing or carrying away of top soil which is rich in plant nutrients.
Top soil can also be blown away by winds, resulting in nutrient reduction in the soil.
(i) This is the removal of nutrients from the top soil to the inner parts of the soil beyond the reach of the roots of plant.
It results in the loss of nutrients such as calcium, magnesium, potassium from the top soil in solution.
(iii) It also results in the accumulation of aluminum and hydrogen ions which become acidic and toxic to plants
(4) pH: The degree of acidity or alkalinity of the soil affects the availability of nutrients both in the soil and also to plants
(i) A low pH (high acidity) will encourage the disintegration of clay minerals 111cc calcium, iron and aluminium ions which are leached away from the soil
(ii) At high pH (high alkalinity) calcium and magnesium ions accumulate in the soll which affects the growth of plants
(iii) A low pH also reduce, the actively of soil living organism which aid the decomposition of organic matter.
(5) Excess of Other Nutrients
(i) The presence of certain element(s) in high concentration may prevent the absorption or utilization of other elements. read about macro and micro-trace elements here
(ii) The concentration of nitrogen and phosphorus in the soil results in the non-availability of potassium.
(iii) This condition results in retarded growth, low yield or even death of the plant.
(6) Oxidation and Reduction of Organic Materials
(i) Some compounds such as ammonium radicals are oxidised to gaseous ammonia.
(ii) Nitrates are also reduced to molecular nitrogen or oxides of nitrogen by denitrifying bacteria.
(iii) These products i.e, ammonium radicals and nitrates which escape into the atmosphere in form of gases make the soil become poorer in nutrients.
HERE YOU WILL FIND EVERY AVAILABLE TOPICS ABOUT AGRICULTURAL SCIENCE AND BIOLOGY. AND THE LINKS TO THEIR VARIOUS SOURCES.
1. ENVIRONMENTAL FACTORS AFFECTING AGRICULTURAL PRODUCTION
3. 52. SOIL MICRO-ORGANISMS